Audiosystem for an automobile

ABSTRACT

The invention relates to an audio system for a motor vehicle, having a plurality of loudspeaker units to which audio signals from various audio signal sources are supplied. The invention proposes designing the supply between at least one audio signal source and at least one loudspeaker unit to be entirely or partially redundant in the form of a primary and a secondary supply.

[0001] The invention relates to an audio system for a motor vehicle in accordance with the precharacterizing part of claim 1.

[0002] In a vehicle having various audio signal sources, e.g. radio, cassette player, CD player, etc, it is known practice to use the loudspeaker units installed in the vehicle for a mobile telephone's hands-free device as well. For this purpose, the audio signal source is turned off when receiving a signal from the mobile telephone, and the mobile telephone is connected to the loudspeaker units in the vehicle by means of a changeover unit. When the call has ended, the previous audio signal source is connected to the loudspeaker units again.

[0003] U.S. Pat. No. 5,420,931 describes an audio system comprising entertainment systems of varying quality. In this case, an entertainment system comprises an audio source and an amplifier. Audio outputs from the high-quality entertainment system, comprising high-quality audio source and high-quality amplifier, can be output on all the vehicle loudspeakers or on a subset thereof. It is also possible for audio outputs from the lower-quality entertainment system, comprising lower-quality audio source and lower-quality amplifier, to be output on all the vehicle loudspeakers or on a subset thereof. The two systems exist side by side with equal rights, i.e. provision is also made for audio signals from one entertainment system to be output on one subset of the vehicle loudspeakers and for audio signals from the other entertainment system to be output simultaneously on the other subset of the vehicle loudspeakers.

[0004] DE 38 28 634 A1 describes a loudspeaker having two oscillating coils which allows information and warnings to be output on the loudspeaker in addition to an audio audio signal source.

[0005] DE 38 42 417 A1 describes an audio system which allows audio messages from a voice memory to be output on loudspeakers.

[0006] DE 42 12 337 A1 describes a safety system in a vehicle comprising anti-lock protection or traction control systems and restraining systems. It describes redundancy in the form of identical duplicate performance of arithmetic operations.

[0007] It is an object of the invention to provide an audio system for a motor vehicle which allows one particular or a plurality of particular audio signal source(s) in the vehicle to be reproduced with a very high level of reliability and availability.

[0008] The invention achieves this object by means of the features of claim 1. The subclaims relate to advantageous refinements and developments of the invention.

[0009] The multiple design of the connection between a particular audio signal source and a loudspeaker unit and the fact that the high-quality amplifier unit for the primary supply is designed redundantly in the secondary supply in the form of an amplifier unit which is provided only for emergencies make it possible for audio signals to be reliably output on at least one loudspeaker in an emergency or in an accident situation, for example. This is used, by way of example, to make at least one loudspeaker reliably available to the voice link between an emergency-call centre and the vehicle occupants. Alternatively, audio signals can be information/warning tones for the driver which he can hear even if the main part of the audio system has failed.

[0010] In an audio system developed on the basis of claim 2, a function check on the primary supply between audio signal source and loudspeaker unit is performed, and the secondary supply is used only if the primary supply has been identified as being faulty. This function check allows the secondary supply to be specifically actuated when required. This prevents a reduction in the sound quality or mixing of sources in the normal situation, since the secondary supply is entirely unused in that case.

[0011] The advantageous form of the audio system in accordance with claim 3 allows reproduction of the particular audio signal source in the best available quality by virtue of, for example, all the loudspeakers in the available audio system being used, provided that the audio system is still operational, to output the voice link to the emergency-call centre. In many cases, the main system will also be operational after an emergency call has been sent, since an emergency call does not always mean that an accident has occurred; instead, breakdown could also be the reason for the emergency call, for example. In a breakdown situation, the main system is generally still operational and its high quality can also be used for voice reproduction in an emergency. In this context, the invention affords the advantage that no additional loudspeakers need to be installed for emergency calls. This results in a reduction in cost, a reduction in the vehicle weight and a saving on installation space. For these reasons, dedicated loudspeakers for emergency calls are usually small and are designed to have lesser sound properties. The invention also uses the high-quality main system in an emergency if it is still operational at that time, and even if this is not the case a regular high-quality loudspeaker in the main system is used via the secondary supply in emergencies. This has the overall result of improved sound quality in emergencies.

[0012] In one advantageous form according to claim 4, it is also possible for the function check on the primary supply to be performed at regular intervals and for the secondary supply to be used to output important information if the primary supply is faulty; said information can comprise traffic reports, driving instructions from the navigational unit or warning and information tones.

[0013] In one advantageous form of the invention according to claim 5, changeover between primary supply and secondary supply is effected by a changeover unit. Such an implementation does not impair the reproduction of the rest of the audio signal sources, since it is possible to dispense with dual-coil loudspeakers. A changeover unit can comprise a control unit and one or more electromechanical or electronic changeover switches.

[0014] In an audio system developed in accordance with claim 6, there is at least one amplifier unit between the audio signal sources and the loudspeaker units, the primary supply between audio signal sources and the amplifier unit being in the form of a data bus. The fact that the primary supply is in the form of a data bus reduces the wiring complexity, and hence the cost and weight of a vehicle are reduced. Normally, audio systems use data buses designed for entertainment purposes which have a high level of flexibility and transmission capacity in the foreground. This is where the invention of designing the supply to the amplifier unit to be redundant is particularly advantageous, since if the data bus is not working the audio signal reaches the amplifier via the secondary supply. In this way, such data buses are provided with the reliability and availability necessary for emergencies or warning information.

[0015] By installing audio source, amplifier unit and/or loudspeaker unit at particularly secure locations, the reliability and availability of the audio system are increased further.

[0016] In one advantageous implementation of the invention in accordance with claim 10, provision is made for the loudspeaker units to be in redundant form. This is particularly beneficial for use of the loudspeaker units in emergencies because it allows the reliability of the system to be increased further. This can be achieved, by way of example, by virtue of the audio signals being supplied to a plurality of loudspeakers at the same time, which means that they are output via the intact loudspeaker units every time. Alternatively, it can be achieved by virtue of the supply of an audio signal to a loudspeaker being preceded by a function check on the loudspeaker, and the audio signal then being output on an operational loudspeaker unit, for example.

[0017] Preferred exemplary embodiments of the invention are described below with reference to the associated drawings, in which, in each case schematically,

[0018]FIG. 1 shows a block diagram of an audio system, and

[0019]FIG. 2 shows a block diagram of an audio system networked via a data bus.

[0020] In normal operation of the audio system shown in FIG. 1, the supply between audio signal sources 1, 2 and 3 runs via an amplifier unit 4 to loudspeaker units 5, 6 and 7. The amplifier unit 4 comprises output stages, preamplifiers and power amplifiers. One of the audio signal sources 1, 2 or 3 is output on the loudspeaker units 5, 6 and 7 or on some of them. It is likewise possible to output two audio signal sources, e.g. the audio signal source 2 on the loudspeaker units 5 and 6 and the audio signal source 3 on the loudspeaker unit 7, which can be in the form of headphones.

[0021] The primary supply between the audio signal source 1 and the loudspeaker unit 5 is thus provided via the amplifier unit 4. The secondary supply between the audio signal source 1 and the loudspeaker unit 5 is provided via an amplifier unit 8.

[0022] The changeover unit 9 comprises a control unit 10 and two changeover switches 11. The control unit can be in the form of an electronic circuit and the changeover switches 11 can be in the form of relays, for example. The control unit 10 performs the function check on the primary supply between the audio signal source 1 and the loudspeaker unit 5. If a fault is identified in the primary supply, the control unit 10 switches the changeover switches 11, so that the secondary supply between the audio signal source 1 and the loudspeaker unit 5 via the amplifier unit 8 is applied.

[0023]FIG. 2 shows a schematic illustration of an audio system networked via a data bus 12 for the interior of a motor vehicle.

[0024] An emergency-call control unit 13 comprises a communication unit 14 for setting up a voice link to an emergency-call centre, an audio signal source 1 which outputs the voice signals for the voice link, a bus controller 13.1, the amplifier unit 8, and the changeover unit 9 containing the control unit 10 and the changeover switches 11. To set up voice links, it is equipped with a microphone 18 and an antenna 19.

[0025] Other units on the data bus, e.g. CD player 15 and video player 16, comprise the audio signal sources 2 and 3 and bus controllers 15.1 and 16.1. An audio control unit 17 comprises a bus controller 17.1 and the amplifier unit 4. The amplifier unit 4 is in the form of an sound system. It amplifies, filters and processes the audio signals supplied by the data bus and supplies them directly to the loudspeakers 5, 6 and 7. The result is individually settable, very high-quality audio. If the data bus is actually still operational in an emergency, the high-quality amplifier unit 4 is used for the voice link for the purpose of amplifying and outputting the speech, by virtue of the voice signal being passed between the audio source 1 and the loudspeakers 5, 6 and 7 via the primary supply, which comprises the data bus 12 and the amplifier unit 4.

[0026] In an emergency, the control unit 10 checks the operability of the primary supply or of parts thereof, e.g. of the data bus 12, of the amplifier unit 4 and/or of the loudspeakers 5, 6 and 7. If the primary supply is unusable, it uses the changeover switches 11 to change over the voice signals from the audio signal source 1 to the secondary supply, which is connected to the loudspeaker unit 5 via the amplifier unit 8. The amplifier unit 8 is provided only for emergencies, i.e. it does not afford total convenience or all the setting options of the amplifier unit 4, but is provided as a dedicated unit just for this instance of application, speech, and is designed for this purpose, i.e. provides a sound appropriate to the emergency. In addition, the amplifier unit 8 is also installed in the housing of the emergency-call control unit 13, which means that, when this unit is installed at a particularly protected location, good crash protection is ensured for the communication module 14, for the changeover unit 11 and for the amplifier unit 8. Since a regular loudspeaker 5 of appropriate size is used for outputting speech in emergencies, the speech quality is better every time than when dedicated, small emergency-call loudspeakers are used. 

1. Audio system for a motor vehicle, having a plurality of loudspeaker units (5, 6, 7) to which audio signals from various audio signal sources (1, 2, 3) are supplied, where amplifier units of varying quality (4, 8) are provided between the audio signal sources and the loudspeaker units, characterized in that the supply between at least one audio signal source (1, 2, 3) and at least one loudspeaker unit (5, 6, 7) is designed to be entirely or partially redundant in the form of a primary and a secondary supply, where a first, high-quality amplifier unit (4) is provided in the primary supply for the audio signals between the at least one audio signal source (1) and the at least one loudspeaker unit (5), and a second amplifier unit (8), which is provided only for emergencies, is provided redundantly in the second supply between the at least one audio signal source (1) and the at least one loudspeaker unit (5).
 2. Audio system according to claim 1, characterized in that a function check on the primary supply is performed, and the secondary supply is used only if the primary supply has been identified as being faulty.
 3. Audio system according to claim 2, characterized in that the check is performed when an emergency is identified.
 4. Audio system according to claim 2, characterized in that the check is performed on a regular basis.
 5. Audio system as claimed in claim 2, 3 or 4, characterized in that changeover between primary supply and secondary supply is effected by a changeover unit (9).
 6. Audio system according to one of the preceding claims, characterized in that the primary supply for the audio signals between the audio signal source (1, 2, 3) and the amplifier unit (4) is in the form of a data bus (12).
 7. Audio system according to one of the preceding claims, characterized in that the at least one audio signal source (1) is installed at a particularly protected location in the vehicle.
 8. Audio system according to one of the preceding claims, characterized in that the second amplifier unit (8) is installed at a particularly protected location in the vehicle.
 9. Audio system according to one of the preceding claims, characterized in that the at least one loudspeaker unit (5) is installed at a particularly protected location in the vehicle.
 10. Audio system according to one of the preceding claims, characterized in that the loudspeaker units (5, 6, 7) are in redundant form. 